* {
    margin: 0;
    padding: 0;
}

.main {
    width: 1000px;
    margin: 0 auto;
}

.banner {
    width: 1000px;
    overflow: hidden;
    position: relative;
}

#ul-imgs {
    width: 5000px;
    margin-left: 0px;
    list-style: none;
}

#ul-imgs.transition {
    transition: all 0.5s linear;
}

#ul-imgs>li {
    width: 1000px;
    float: left;
}

#ul-imgs img {
    width: 1000px;
}

.ul-idxs {
    width: 100px;
    margin: 0 auto;
    list-style: none;
    position: absolute;
    bottom: 25px;
    left: 50%;
    margin-left: -50px;
}

.ul-idxs>li {
    float: left;
    width: 15px;
    height: 15px;
    background-color: aliceblue;
    border-radius: 50%;
    margin: 0 5px;
    cursor: pointer;
}

.ul-idxs>.active {
    background-color: blue;
}

.btn-left,
.btn-right {
    width: 60px;
    height: 100%;
    position: absolute;
    top: 0;
    background-repeat: no-repeat;
    background-position: center;
    cursor: pointer;
}

.btn-left {
    left: 20px;
    background-image: url("./image/carousel_item/left_ar.png");
}

.btn-right {
    right: 20px;
    background-image: url("./image/carousel_item/right_ar.png");
}

.btn-left:hover,
.btn-right:hover {
    background-size: 40px 70px;
}